1. Field of Invention
The present invention relates to methods for manufacturing organic EL (electroluminescence) devices. The organic EL devices can be used, for example, as displays of a television and a computer, and light sources, such as a backlight of a liquid crystal display.
2. Description of Related Art
Recently, as a self-luminous display used in place of a liquid crystal display, organic EL devices (light-emitting devices having a structure in which an organic light-emitting layer is provided between an anode and a cathode) have rapidly been developed. As a material for the light-emitting layer used for an organic EL device, there are organic materials with low molecular weight such as an aluminum quinolinol complex (Alq3), and organic materials with large molecular weight such as polyparaphenylene vinylene (PPV). A light-emitting layer composed of an organic material with low molecular weight can be formed by a deposition method as disclosed in, for example, Appl. Phys. Lett. 51(12), 21 Sep. 1987, p. 913. A light-emitting layer composed of an organic material with large molecular weight is formed by a coating method as disclosed in, for example, Appl. Phys. Lett. 71(1), 7 Jul. 1997, p. 34.
For example, in an organic EL device for use in a display, it can be necessary to arrange a light-emitting layer at a position on a substrate corresponding to each pixel. In addition, in the cases of a color display and a white light source, it can be necessary to arrange each of light-emitting layers having three primary colors at each corresponding position on a substrate. Accordingly, when the arrangement of light-emitting layers can be performed by an ink-jet method, coating and patterning can be simultaneously performed, and hence, patterning with high accuracy can be performed in a short period of time. In addition, since a material used in this method can be minimized, the material can be efficiently used, and reduction in production cost can be effectively achieved.
Previously, when light-emitting layers are formed into a predetermined pattern by an inkjet method, banks composed of an insulating layer can be formed, and the light-emitting layers are formed in areas surrounded thereby. Whether or not anodes are patterned corresponding to the light-emitting area, the formation of the insulating layers as described above can be performed.